test: fat: add test of non-contiguous file reads

In my patch series to replace fs/fat with "ff.c", I enhanced ff.c to
optimize file reading, so that reads of contiguous clusters are submitted
to the IO device as a single read. This test attempts to torture-test
edge-cases of that enhancement.

BTW, the only way I found to validate that this script actually does
create non-contiguous files was to manually inspect the FAT bitmap in a
hex dump of the FAT image. hdparm --fibmap doesn't work on loop-mounted
filesystems. filefrag -v -e seems to lie about files being contiguous
when they aren't.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Stephen Warren 2015-10-03 13:56:47 -06:00 committed by Tom Rini
parent 7861204c9a
commit 4a28274227

113
test/fs/fat-noncontig-test.sh Executable file
View File

@ -0,0 +1,113 @@
#!/bin/bash
# (C) Copyright 2015 Stephen Warren
#
# SPDX-License-Identifier: GPL-2.0+
# This script tests U-Boot's FAT filesystem code's ability to read non-
# contiguous files.
# When porting the ff.c FAT parsing code into U-Boot, it was found that ff.c
# always reads files cluster-by-cluster, which results in poor performance.
# This was solved by adding a patch to ff.c to coalesce reads of adjacent
# clusters. Since this patch needed to correctly handle non-contiguous files,
# this test was written to validate that.
#
# To execute the test, simply run it from the U-Boot source root directory:
#
# cd u-boot
# ./test/fs/fat-noncontig-test.sh
#
# The test will create a FAT filesystem image, record the CRC of a randomly
# generated file in the image, build U-Boot sandbox, invoke U-Boot sandbox to
# read the file and validate that the CRCs match. Expected output is shown
# below. The important part of the log is the penultimate line that contains
# either "PASS" or "FAILURE".
#
# mkfs.fat 3.0.26 (2014-03-07)
#
#
# U-Boot 2015.10-rc4-00018-g4b22a3e5513f (Oct 03 2015 - 13:49:23 -0600)
#
# DRAM: 128 MiB
# Using default environment
#
# In: serial
# Out: lcd
# Err: lcd
# Net: No ethernet found.
# => host bind 0 sandbox/fat-noncontig.img
# => load host 0:0 1000 noncontig.img
# 33584964 bytes read in 18 ms (1.7 GiB/s)
# => crc32 1000 $filesize 0
# crc32 for 00001000 ... 02008743 ==> 6a080523
# => if itest.l *0 != 2305086a; then echo FAILURE; else echo PASS; fi
# PASS
# => reset
#
# All temporary files used by this script are created in ./sandbox to avoid
# polluting the source tree. test/fs/fs-test.sh also uses this directory for
# the same purpose.
#
# TODO: Integrate this (and many other corner-cases e.g. different types of
# FAT) with fs-test.sh so that a single script tests everything filesystem-
# related.
odir=sandbox
img=${odir}/fat-noncontig.img
mnt=${odir}/mnt
fill=/dev/urandom
testfn=noncontig.img
mnttestfn=${mnt}/${testfn}
crcaddr=0
loadaddr=1000
for prereq in fallocate mkfs.fat dd crc32; do
if [ ! -x "`which $prereq`" ]; then
echo "Missing $prereq binary. Exiting!"
exit 1
fi
done
make O=${odir} -s sandbox_defconfig && make O=${odir} -s -j8
mkdir -p ${mnt}
if [ ! -f ${img} ]; then
fallocate -l 40M ${img}
mkfs.fat ${img}
sudo mount -o loop,uid=$(id -u) ${img} ${mnt}
for ((sects=8; sects < 512; sects += 8)); do
fn=${mnt}/keep-${sects}.img
dd if=${fill} of=${fn} bs=512 count=${sects} >/dev/null 2>&1
fn=${mnt}/remove-${sects}.img
dd if=${fill} of=${fn} bs=512 count=${sects} >/dev/null 2>&1
done
rm -f ${mnt}/remove-*.img
# 511 deliberately to trigger a file size that's not a multiple of the
# sector size (ignoring sizes that are multiples of both).
dd if=${fill} of=${mnttestfn} bs=511 >/dev/null 2>&1
sudo umount ${mnt}
fi
sudo mount -o ro,loop,uid=$(id -u) ${img} ${mnt}
crc=0x`crc32 ${mnttestfn}`
sudo umount ${mnt}
crc=`printf %02x%02x%02x%02x \
$((${crc} & 0xff)) \
$(((${crc} >> 8) & 0xff)) \
$(((${crc} >> 16) & 0xff)) \
$((${crc} >> 24))`
./sandbox/u-boot << EOF
host bind 0 ${img}
load host 0:0 ${loadaddr} ${testfn}
crc32 ${loadaddr} \$filesize ${crcaddr}
if itest.l *${crcaddr} != ${crc}; then echo FAILURE; else echo PASS; fi
reset
EOF